Just a burnt out town, just a one horse scene So I'm an anthropology major at MIT. Call it what you like, I call it my job ticket. You can take the carnie out of the circus, but in the end, I'm just a Big Top drop out. [College!Clint RP blog. Sideblog of beyondmysights.]
contrary to popular belief, I am responsible enough
to tutor. Apparently — y’know, maybe I should tutor
you. Promise — won’t even charge you full price. And
secondly? You’re the world’s worst liar. I can’t believe
you beat me in poker last night.”
Okay, first off -- I don't think you know a damn thing about
anthropology, and secondly? Only when I want to be. You
know, helps when people think you're a shitty liar -- then
they think they've got your number. You could learn a few
things from me, kid."
NON SPECIFIC INFECTIOUS DISEASES & DENTAL DISEASES
Infections, in the most general terms, are caused by an invasion of the body by pathogenic micro-organisms which multiply and may cause damage to the bone and/or surrounding tissues. Infections can be classed as 'specific' or 'non-specific'.
Since bone can only react two ways to infection -- the formation or the destruction of bone -- it can be difficult to provide a differential diagnosis, and many times the infection identified will be non-specific.
Infectious diseases (bacteria and viruses in particular) probably accounted for the majority of deaths in the past without access to antibiotics. A large proportion of these infections were spread via the faeco-oral route to unclean water.
Certain groups were particularly vulnerable - for instance, infants and young children were highly vulnerable to cute gastrointestinal and respiratory infections. Infectious diseases therefore impacted both the quantity of deaths and the demographic patterning of deaths in past populations.
How does the body respond to infections?
Acute inflammation often accompanies infection, and includes four components:
Hyperaemia - the presence of an abnormally large blood supply in which the blood vessels are dilated and the flow of blood is slower.
Permeability - Increased permeability in the smaller blood vessels, allowing the body to position blood elements in the area in order to heal the injured tissue or combat any introduced foreign agents.
Exudation - the movement of fluid and blood cellular elements into the injured tissue(s)
Oedema - accumulation of fluids within the tissue(s) that then slows or stagnates blood flow. This acts to localize the inflammatory process.
All pathological changes in bone result from an imbalance in the normal equilibrium of bone formation and resorption.
There are two routes of infection:
Direct spread of a pathogen from an adjacent soft tissue (localised)
Haematogenous spread from the bloody supply throughout the body (diffuse)
Infection following compound fracture.
Localised periostitis associated with a skin ulcer.
Direct spread
a) Dental abscesses
b) Maxillary sinusitis, associated with environmental factors such as low air quality and pollutants
c) Periostitis on the ventral surfaces of the ribs, strongly linked with e.g. tuberculosis or other lung infections
Haematogenous spread
Most commonly caused by the pathogens staphyloccus aureus, streptococcus pyogenes, streptococcus pneumaniae, and escherichia coli.
Forms of general bone infection
Non-specific infections:
Periostitis -- inflammation of the periosteum, resulting in periosteal reaction
Osteoitis -- inflammation of the inner structures of the compact bone
Osteomyelitis -- inflammation of the medullary cavity
The manifestation of periostitis, osteitis and osteomyelitis are all caused by an unspecified micro-organism -- that is to say, it is caused by a specific microbe, but we as anthropologists cannot tell which.
Describing bone formation
When the evidence of non-specific infection is found on bones, it is important to be able to describe accurately what is present before any attempt at differential diagnosis can be made.
Woven bone refers to low density spicules or layers of bone that forms rapidly in response to infection.
Lamellar or compact bone refers to high density tissue with an organised structure, often striated. It form slowly from chronic conditions or the healing of woven bone.
Porous bone refers to well organised but porous or softly grained bone.
Non-specific infections
Osteitis -- an inflammatory process that primarily affects the inner structures of compact bone (i.e. Haversian canals and bone adjacent to medullary cavity).
Osteomyelitis -- an inflammation of the medullary cavity and inner cortex. It is almost always cause by pyogenic micro-organisms. Infection may result from one of three sources:
Direct spread of pathogen from infected local tissues
Haematogenous spread through the blood stream, where the organism enters the blood from a septic focus elsewhere (the most common cause)
Direct implementation of the pathogen via penetrating wound, compound fracture, or surgery.
The following stages are observed in osteomyelitis:
Sequestrum: segment of necrotic bone separated from the living bone by granular tissue
Involucrum: new layer of living bone formed around the dead bone
Cloaca: opening in the involucrum to allow the passage and discharge of granulation tissue and sequestra from the medullary canal.
Subsequent perforation of the skin forms a drainage channel, which is termed a fistula or sinus.
Septic arthritis -- most commonly caused by staphylococcus aureus, an infection spread via bloodstream to the joints. It is sometimes (mistakenly) grouped with degenerative joint diseases, but is unrelated to age or joint use.
It is most common in the knee and hip, but can affect any joint, including the CMC and TMT joints.
Dental pathology
Calculus -- mineralised form of dental plaque, which are adhered oral microbes generally kept in check by oral defences. A low pH favours the accumulation of plaque, which will then mineralise in a stable acid environment.
Although it is generally formed on the buccal surfaces of teeth at the cemento-enamel junction, it can also form more widely, onto the occlusal surface of the tooth. This would indicate that the tooth was not being used for chewing -- either because of ante-mortem loss of a corresponding tooth, or the inability to move the jaw.
Caries (carious lesion sg.) -- the progressive decalcification/demineralisation of enamel and dentine by acidic bacterial excretions resulting from the digestion of fermentable carbohydrates, especially refined sugars. Since carious lesions are caused by acidic products of bacteria, they provide favourable conditions for the formation of dental calculus, and thus the two often go hand-in-hand.
Periodontal disease -- the immune reaction to oral microboime. Minor reaction results in gingivitis, whilst more severe reaction results in periodontitis, which affects the bone. It is characterised by the form of the alveolar bone.
Ante-mortem tooth loss -- can be as a result of advanced dental pathology, trauma, intentional removal or advanced age. Given time, the root space will resorb. The complete loss of dentition results in edontulism.
Apical granuloma -- occurs when a tooth has died and a cyst forms around the root.
(N.B. -- abscesses are pyogenic, smooth-margined lesions, whereas cysts are membrane-bound, sharp-edged lesions.)
There are also numerous developmental defects of the teeth, which are variable in their rarity. These include:
Impaction
Hyperdontia/hypodontia
Macrodontia/microdontia
Aplasia
Rentention (becomes ogliodontia when 5+ missing)
Crowing/spacing (diastema)
Gemination
Tori
Dental wear
Dental wear depends on diet, use of teeth and other external factors, and there are various types of wear that can be seen.
Abrasion - wear from contact with abrasive particles in food
Attrition - wear from tooth-tooth contact
Occlusal wear - removal of enamel and dentine from chewing surfces
Interproximal wear - development of wear facets between adjacent teeth
Activity-related wear - related to occupational activities
Dental modification - cultural practices of filing, shaping or inlaying teeth.
The gluteal region can be divided into the gluteal muscles and the lateral rotators, which have separate functions.
The gluteal muscles, (gluteus maximus, gluteus medius and gluteus minimus) can be further divided, since gluteus maximus assists in different actions from the other gluteal muscles.
Gluteus medius and minimus both insert onto the greater trochanter (medius laterally and minimus anteriorly); both abduct and medially rotate the thigh, as well as stabilising during locomotion; both are served by the superior gluteal nerve, and both are served by the superior gluteal artery.
The lateral rotators all, to no one's surprise, laterally rotate the femur. Piriformis also aids in abduction, and obturator externus stabilise the femoral head in the acetabulum.
The first group (piriformis, obturator internus, and the gemelli) all insert onto the greater trochanter of the femur. The gemelli and quadratus femoris share origins on the ischium, and the nerves are nerve to piriformis (piriformis), the nerve to obturator internus (superior gemellus and obturator internus) and the nerve to quadratus femoris (inferior gemellus and quadratus femoris).
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